The present invention relates to a portable microfilm reader for projecting images recorded on a microfilm onto a self-contained viewing screen and more particularly, to a microfilm reader which can be folded in the form of a flattened box-like configuration for carrying convenience.
Microfilm readers are widely used to retrieve and view any one of a great number of images of documents, drawings and the like recorded on a small size of microfilm, for example a 16 mm microfilm. In such a microfilm reader, each frame of the microfilm has to be magnified to a A-4 size of image. As is well known in the art, the microfilm reader comprises a microfilm loading section; an illumination section for illuminating a retrieved frame of the microfilm; an optical system including a reflection mirror for magnifying and projecting each frame of the microfilm; and a viewing screen onto which a magnified image is projected.
Among these microfilm readers, there has been known a compact, foldable microfilm reader provided with a viewing screen capable of being folded or pushed down toward a main body of the microfilm reader containing the microfilm loading section and the illumination section therein, the microfilm reader being disclosed in U.S. Pat. Nos. 3,667,839, 3,700,321, 3,785,728, 3,814,514, 4,432,619, 3,625,333, DE Pat. Nos. 3,223,906, and 3,034,401. Further disclosed in U.S. Pat. No. 4,640,597 is a microfilm reader which can be folded in the form of a generally flattened box-like configuration. Such the microfilm reader can be folded compact, thereby very convenient to carry about.
In the above-described conventional microfilm reader of the type having a viewing screen capable of being pushed down, the viewing screen is left open to the view when the viewing screen is pushed down to fold the microfilm reader. For this reason, the surface of the viewing screen is apt to take scratches and, in the extreme case, to be damaged when being carried about.
For increasing contrast of the image projected on the viewing screen unfolded or risen up at a certain angle, the microfilm reader requires to avoid ambient light to stream behind the viewing screen. For this requirement, the microfilm reader of this type is further provided with a light shielding hood for enclosing a space behind the viewing screen in a box-like shape when the viewing screen is risen up. The light shielding hood should be desirably folded and laid under the viewing screen when the viewing screen is pushed down. The microfilm reader provided with such the box-like hood is complicated in structure, in particular, in folding mechanism for the box-like hood and disadvantageous in respect of space saving. Furthermore, the provision of the complicated, space consuming hood folding mechanism is an obstacle to the compactness of the microfilm reader.
In view of the above, an improved compact, foldable microfilm reader has been proposed in U.S. Pat. No. 4,629,299 assigned to the same assignee of the present application. The microfilm reader disclosed therein comprises a viewing screen capable of being pushed down and a top cover which are independently provided and supported. Furthermore, the microfilm reader requires to pull out a slide member supported by its main body before the viewing screen is risen up. The provision of the slide member with its associated members makes the microfilm reader complicated in structure and inconvenient in operation.